a) Field of the Invention
The invention relates to surgical forceps having distal mouth parts, at least one mouth part of which can be movably actuated against the other by means of a proximal handle, wherein the force exerted when actuating the handle can be transferred to the movable mouth part by means of an axially displaceable rod, and wherein overload protection is provided which is effective in the case of overload with danger of breakage and limits the closing force of the mouth parts to a preset value.
b) Description of the Prior Art
Surgical forceps of the type mentioned above having cutting, stamping or clamping and holding distal mouth parts must be protected against overload and danger of breakage, particularly since the force exerted by the handle on the distal mouth parts may be relatively large as a result of the existing leverage.
In a known design of forceps of this type, it is possible to achieve overload protection by means of safety devices which are introduced onto the handle, such as for example according to German Patentschrift 3 601 166 by a spring, which, according to a first exemplary embodiment, bridges the two-part forceps grip arranged to be pivotable under spring pretension and, according to a second exemplary embodiment, bridges the connecting and forcing rod connected to the pivotable forceps mouth part under spring pretension, and absorbs the further compressive force exerted on the two forceps grips when the breaking force is exceeded.
In both embodiments, only the movable grip section of the handle is deflected further on reaching a certain force and the mouth part no longer moves, but the force exerted on the mouth parts increases further in accordance with the spring characteristic. Furthermore, it is not possible for the operator to clearly perceive in which actuation position the actuation force exceeds the spring pretension, since this transition is fluid. Uncertainties may arise during handling because of this.
In German Offenlegungsschrift 3 709 067, a disengaging coupling is provided between the movable grip section and the connecting and forcing rod, wherein a coupling part mounted resiliently in a grip section engages and disengages in a recess in the rod if a certain force is exceeded. This transition is not fluid, it is abrupt, wherein the movable grip section is completely uncoupled by the rod. This design also conceals uncertainties in the handling.
It is the object of the invention to find overload protection for surgical forceps of the type mentioned which acts safely and makes it possible for the operator to work with sensitivity, wherein the moment of onset of overload should be detectable by the operator.